1. Field of the Invention
The present invention relates to an electric clamp apparatus which makes it possible to clamp a workpiece to be positioned and transported on a carriage, for example, in an automatic assembling line.
2. Description of the Related Art
Conventionally, for example, a workpiece such as an engine is transported by a carriage in an automatic assembling line for automobiles. A variety of machining steps or assembling steps are performed at respective stations.
It is necessary at each of the stations that the positioning is performed to obtain a predetermined position in order to fix the workpiece to a jig. In recent years, a system is adopted, in which a clamp apparatus is provided for the carriage itself, the workpiece is transported while being clamped on the carriage, and only the carriage is positioned at each of the stations.
In this system, a fluid pressure-operated cylinder, for example, a pneumatic cylinder is used as a driving source for driving the clamp apparatus.
In view of the above, the present applicant has proposed an electric clamp apparatus in which the clamping force can be further increased, the complicated arrangement of air piping or the like can be dissolved, and the installation space can be effectively utilized (see Japanese Patent Application No. 11-282195).
The present invention has been made in relation to the proposal described above, a general object of which is to provide an electric clamp apparatus which makes it possible to realize a small size by forming the entire apparatus to have a flat configuration with a narrow width and which makes it possible to smoothly regulate a range of rotation of an arm by means of a simple structure.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.